The flowability and high-temperature resistance of manufactured sand concrete: An exploration for high-rise buildings

Abstract

Abstract The depletion of natural concrete aggregates, e.g., river sands, is a gradual process, and hence, manufactured sand concrete (MSC) is widely used in various construction projects. The flowability and high-temperature resistance of MSC directly determine the transport of fresh concrete and the fire resistance of high-rise buildings. In this study, MSC with different superplasticizer contents and sand ratios was prepared and its flowability and high-temperature resistance were studied. Scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP) were used to characterize the microstructure and porosity of MSC. The flowability of MSC with higher than 0.75% superplasticizer content or lower than 43% sand ratio is suitable for super high-rise buildings according to GB/T 50081-2019. The mechanical properties of other MSC meet the C30 requirements except for the MSC with a sand ratio of 48%. And the relatively high superplasticizer content or low sand ratio can make the denser structure and lower porosity of MSC. In addition, the MSC with relatively high superplasticizer content and low sand ratio exhibits better resistance to high temperatures due to a denser structure. This study provides theoretical guidance for using MSC in high-rise buildings and studying fire performance.